The endocardium is the membrane that lines the inside of the heart and surfaces of the heart valves. In infective endocarditis, this membrane becomes inflamed due to an infection, usually with bacteria, but occasionally with other microorganisms.
The infection may occur during surgery (including dental surgery) or another invasive procedure (such as insertion of a catheter), through breaks in the skin, or as a result of intravenous drug use.
People whose endocardium has previously been damaged are particularly vulnerable, as are those who have an artificial heart valve and people with reduced immunity. Symptoms of infective endocarditis, which may come on suddenly or gradually, include persistent fever, fatigue, and breathlessness. Untreated, it may lead to life-threatening complications, such as heart failure or stroke.
Treatment is usually with medication, although surgery is sometimes necessary.